I hooked up the simplest imaginable DAC to my Pumpkin/AX setup. Just for fun and out of curiousity. (And ofcourse for liking a solder job!) How small and simple does it get? I dont know, but a DAC of 125X125mm is pretty small I guess! (5"X5") Here is pic of the front, its a TDA1543 DAC.
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steenoe said:Yes, that is probably the next step. I will try and figure out something that can be squeezed onto the board. It will have to be fed by the single-ended supply though.
Funny enough, there is a little room left on the perfboard
.........
"buffer for Blues" or Borbely buffer ( two N Jfets in toob fashion
)steenoe said:.........
BTW, I consider rebuilding the Pumpkin and use 2 case's instead of 1. The wooden box is not able to dissipate the heat, really. It runs a bit warm, inside. Alternatively the top and bottom plates could be filled with holes, but that wouldnt look too good.
well - YOU asked for F4 capable preamp ; now suffer
I could make you one with 1/10 of dissipation , but that was outa fashion ........
hi!
You sad the truth, model 8075 on page 7 but i, cuted left and right side. It look beter.
Regards zeoN_Rider
steenoe said:
This might be the company that produce the cool looking heatsinks. Go through the catalouge and you will find some extrutions that look pretty much like those on the pic.
http://www.newtronic.dk/picture/upload/Pada_83_110.pdf
You sad the truth, model 8075 on page 7 but i, cuted left and right side. It look beter.
Regards zeoN_Rider
Steen - I just tried for you that version ( if I'm not wrong - PD's ?) of simple 1543 DAC , feeding 22K input impedance of next stage ;
there is not enough dynamics ; sound is -sorta interesting (different than SSDac with xformers , certainly ) but just with occasional glimpse of life in it ; details are almost there , but everything is somehow flat ;
you'll always know that impedance mismatch is in case , if you have wakoo response of volume control ....... turning it up almost without normal response , and then suddenly you have enough volume ;
purely subjective described ......
there is not enough dynamics ; sound is -sorta interesting (different than SSDac with xformers , certainly ) but just with occasional glimpse of life in it ; details are almost there , but everything is somehow flat ;
you'll always know that impedance mismatch is in case , if you have wakoo response of volume control ....... turning it up almost without normal response , and then suddenly you have enough volume ;
purely subjective described ......
steenoe said:
This might be the company that produce the cool looking heatsinks. Go through the catalouge and you will find some extrutions that look pretty much like those on the pic.
http://www.newtronic.dk/picture/upload/Pada_83_110.pdf
But isn't that what we have been using since forever?
Magura
jacco vermeulen said:
A pair of Pumpkin and Shunty!
The heatsink on the Pumpkin is an old cheapie NOS that I found in the cabinet. It was bought long time ago for less than US$2. I saw and adapt it for use on the Pumpkin. Now it measures the full width of the PCB and is 50mm high, 15mm deep and has a base plate of 5mm thick, fixed with stainless steel bolt and isolated from ground plane with teflon washers.
The heatsink for the pre-regulator of the Shunty is also an old cheapie NOS that I bought for less than US$1.0. It protrudes a couple of mm beyond the PCB. The CCS and the shunt Darlington transistors are installed on 2 RISC CPU heatsinks that measures 51mm x 54mm and 16mm deep that have base plates of 5mm. The 2 heatsinks are bolted together using 25mm Al flat bar. These CPU heatsinks are provided with fans but have been taken out and thrown away! They cost about US$2.50 a piece in the junkyard here.
Zen Mod said:
it's always nice to see other fellow junkdog
I just can't find anything better than these CPU heatsinks in the local market. They looked like gems to me when I spotted them. They have some 3M VHB (Very High Bond Joining System) glue on the base plate and I find the most convenient way to remove it is to rub it out with my bare thumb. Now I can't go to the US for I have lost all my finger print on my thumbs!
jacco vermeulen said:
No, thank you. These junk heatsinks need a lot of metal working.
jacco vermeulen said:
I have tested the pair at an ambient temperature of about 29 degree Celsius, still air. Everything goes fine and the heatsinks on the Shunty are warm to the touch only. That one on the Pumpkin is hotter but still don't burn my fingers.
Don't have thermal couple for my Fluke 189 for temperature measurement but may buy one some day. Will let you know the ¢XC/W then.
Manu said:
pooftaaaahhhhh , puffer , stossdampfer
I dunno exact number or name of the pdf - go to Borbely's and look for "new Jfet frontiers"
naaaah ......... just download all pdfs , and you'll find mucho dobrih stvari
on the other thought - look for "Borbely " and "Papa" on these DVDs I sent you .
Hi Manu,
Papa said that he will publish a buffer article. In the meantime, look here:
http://www.diyaudio.com/forums/showthread.php?postid=1520943#post1520943
More precisely, you will need only this:
Papa said that he will publish a buffer article. In the meantime, look here:
http://www.diyaudio.com/forums/showthread.php?postid=1520943#post1520943
More precisely, you will need only this:
Attachments
Ah... Yes.
Thanks crazy cat.
The perpective of Papas Buffer-paper is a good news for me.
Its always amazing how this great artist manage to adress in one same article both smart e-ingénieurs and stupid french monkey. With good results I think...
Manu
PS
(Is it hot in Dutch-land as it is in Ostrija these days? ... We have hochsummer time ... I don't complain. Just that Aleph needs some additional cooling)
Steen : Are you sure you have to change to metal-case? A pity considering your beautiful wood-work. More air flow inside could mebbe cure the heatproblem? No?
Thanks crazy cat.
The perpective of Papas Buffer-paper is a good news for me.
Its always amazing how this great artist manage to adress in one same article both smart e-ingénieurs and stupid french monkey.
With good results I think...Manu
PS
(Is it hot in Dutch-land as it is in Ostrija these days? ... We have hochsummer time ... I don't complain. Just that Aleph needs some additional cooling)
Steen : Are you sure you have to change to metal-case? A pity considering your beautiful wood-work. More air flow inside could mebbe cure the heatproblem? No?
Cook Book - few more lines
as always - Cook Book supplemented with few more lines ;
they are :
"- My mistake was that I wrote ZY10 zenners in Shunty (D1 to D5, D1ato D5a)
; all you need is ZF , which are just generic 400mW ones ; now corrected in parts table .
- In case that you are fluffy with setting absolute offset (DC voltage between plus and minus
outputs of Pumpkin ) , you'll have replicated DC on both INPUTS of Pumpkin ........ exactly
divided by ratio of feedback net .
That will result in screechy noise during volume pot turning .....
cure is simple - Papa-like ....... just include 2u2 good cap on each input leg (both + and -)
between pot and inputs ; that will block DC to reach pot .
Hehe - that cure is certainly less evil than using any kind of Servo"
regarding these caps - Holger (HB) already sez long time ago that he even will not try his
without input caps .........
as usuall , Cook Book can be found HERE
as always - Cook Book supplemented with few more lines ;
they are :
"- My mistake was that I wrote ZY10 zenners in Shunty (D1 to D5, D1ato D5a)
; all you need is ZF , which are just generic 400mW ones ; now corrected in parts table .
- In case that you are fluffy with setting absolute offset (DC voltage between plus and minus
outputs of Pumpkin ) , you'll have replicated DC on both INPUTS of Pumpkin ........ exactly
divided by ratio of feedback net .
That will result in screechy noise during volume pot turning .....
cure is simple - Papa-like ....... just include 2u2 good cap on each input leg (both + and -)
between pot and inputs ; that will block DC to reach pot .
Hehe - that cure is certainly less evil than using any kind of Servo"
regarding these caps - Holger (HB) already sez long time ago that he even will not try his
without input caps ......... as usuall , Cook Book can be found HERE
Manu said:
All ya guy's are nut's
I know I asked for F4 preamp, and I really like the sound of it.... Well, I will simply build the psu into a seperate case, just like the one my Pumpkin is in right now Surely, two cases dissipates double up on the heat, right? I have ordered the wood for it allready. BTW its Erocco-teak. Just hope I didnt butcher a rainforest
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